The document RD Sharma Solutions - Ex-25.1, Data Handling IV Probability, Class 7, Math Class 7 Notes | EduRev is a part of the Class 7 Course RD Sharma Solutions for Class 7 Mathematics.

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**A coin is tossed 1000 times with the following frequencies:**

Head: 445, | Tail: 555 |

**When a coin is tossed at random, what is the probability of getting (i) a head? (ii) a tail?**

Total number of times a coin is tossed = 1000

Number of times a head comes up = 445

Number of times a tail comes up = 555

(i) Probability of getting a head

(ii) Probability of getting a tail =

**A die is thrown 100 times and outcomes are noted as given below:**

Outcome: | 1 | 2 | 3 | 4 | 5 | 6 |

Frequency: | 21 | 9 | 14 | 23 | 18 | 15 |

**If a die is thrown at random, find the probability of getting a/an.**

(i) 3

(ii) 5

(iii) 4

(iv) Even number

(v) Odd number

(vi) Number less than 3.

**Answer 2:**

Total number of trials = 100

Number of times "1" comes up = 21

Number of times "2" comes up = 9

Number of times "3" comes up = 14

Number of times "4" comes up = 23

Number of times "5" comes up = 18

Number of times "6" comes up = 15

(i) Probability of getting 3

(ii) Probability of getting 5

(iii) Probability of getting 4

(iv) Frequency of getting an even no. = Frequency of 2 + Frequency of 4 + Frequency of 6 = 9+ 23 + 15 = 47

Probability of getting an even no.

(v) Frequency of getting an odd no. = Frequency of 1 + Frequency of 3 + Frequency of 5 = 21+ 14 + 18 = 53

Probability of getting an odd no

(vi) Frequency of getting a no. less than 3 = Frequency of 1 + Frequency of 2= 21 + 9 = 30

Probability of getting a no. less than 3

**A box contains two pair of socks of two colours (black and white). I have picked out a white sock. I pick out one more with my eyes closed. What is the probability that I will make a pair?**

No. of socks in the box = 4

Let B and W denote black and white socks respectively.

Then we have:

S = {B,B,W,W}

If a white sock is picked out, then the total no. of socks left in the box = 3

No. of white socks left = 2-1 =1

Probability of getting a white sock

**Two coins are tossed simultaneously 500 times and the outcomes are noted as given below:**

Outcome: | Two heads(HH) | One head(HT or TH) | No head(TT) |

Frequency: | 105 | 275 | 120 |

**If same pair of coins is tossed at random, find the probability of getting (i) Two heads (ii) One head (iii) No head.**

Number of trials = 500

Number of outcomes of two heads (HH) = 105

Number of outcomes of one head (HT or TH) = 275

Number of outcomes of no head (TT) = 120

(i) Probability of getting two heads

(ii) Probability of getting one head

(iii) Probability of getting no head